Ventilators are used in a variety of applications to provide non-invasive (e.g., via a mask) and invasive (e.g., via an endotracheal tube) ventilation of a patient.
A Safety Valve, Positive Pressure Relief Valve (PPRV) and Negative Pressure Relief Valve (NPRV) are components in a ventilator and are often required by standards applicable to ventilators. Normally in known ventilators, the safety valve, PPRV and NPRV are three separate parts and each provides a specific function. Notably, the safety valve ensures that the pressure in the patient circuit does not exceed a certain level; the PPRV allows for inhalation at a predetermined (positive) pressure; and the NPRV allows air from the ambient to be delivered to the patient when the negative pressure in the patient circuit exceeds a predetermined (negative) pressure (e.g., during ventilation system failure).
Known safety valves, PPRVs and NPRVs are normally purely mechanical in nature. As such, a threshold pressure is set (e.g., by a spring mechanism) and cannot be varied to accommodate different patient requirements during ventilation. For example, the safety valve can only be set to a specific value for relieving pressure above the highest pressure level in the ventilator, and the NPRV can be set to a specific negative pressure level for relieving pressure below a lowest pressure level in the ventilator. Additionally, over time in known actuators, the accuracy of the valve can be diminished.
What is needed is an apparatus and method for use in a ventilator that overcomes at least the shortcomings of the known apparatuses described above.